The present invention relates to an electronic endoscope, and more particularly to a PCB (Printed Circuit Board) structure for a scope unit of electronic endoscope.
A medical electronic endoscope is generally provided with a processor having a light source, image processing unit and the like, and an electronic scope (a scope unit) having a portion to be inserted in a human body. The electronic scope has a light guide, which receives the light emitted by the light source from the processor, and illuminates inside the human body, and a CCD (Charge Coupled Device) which captures an image of the illuminated portion.
In such an electronic endoscope, electronic circuits are provided. Typically, an electronic circuit is installed inside a section of the electronic scope in a form of a PCB. In a conventional electronic scope, the PCB is formed of a single substrate having a relatively large area. Generally, such a PCB is provided at a connection section at which the scope unit is connected to the processor. Since the PCB has a relatively large area, the connection section of the endoscope unit becomes large. The large scope unit is troublesome in handling, i.e., in each of operating, carrying and storage, the larger scope is burdensome to the operator.
Conventionally, a structure, in which two PCBs having substantially the same size are piled, has been known. In such a structure, the circuit is divided into two portions, which are formed into the two PCBs respectively.
However, in such a structure, since one circuit pattern is divided into two patterns, if the two PCBs are arranged such that large size electrical elements of the two PCBs are arranged to face outside and the circuit patterns of the two PCBs face each other, it is very troublesome to electrically connect portions of one circuit pattern to portions of the other with wires.
Specifically, after the two PCBs are piled, it is difficult to wire. For example, soldering the wires are difficult with the PCBs piled if the printed patterns face each other. It may be possible to pile the PCBs after the wiring. However, in such a case, the wires are longer than the clearance between the two PCBs, depending on the configuration of the PCBs, and wires and/or soldered portions may easily be broken. Therefore, the piling procedure should be performed with the greatest care. If the PCBs are arranged such that the circuit patterns are located outside the piled PCBs, room for wires connecting the PCBs is required, which obstructs downsizing of the electronic scope.